Man page issues: logb, significand, cbrt, log2, log10, exp10

[Paul Zimmermann]

       Hi Wilco,

> The worst case error of MUSL is 4.14 ULP vs 2.01 ULP of the old GLIBC exp10 [1].
> 
> And the new exp10 in GLIBC is 0.513 ULP [2].

yes the new exp10 is more accurate, nice work!

> As I pointed out in the PR, it would be reasonable for compilers to convert
> pow (10, x) into exp10 (x) when it is known there is a good implementation
> available - in GLIBC, exp10 is both faster and slightly more accurate than pow.

ok at compile time, but there should be a way to disable this optimization,
for example if you want to compare pow(10,x) and exp10(x). (At run time
such a conversion would slow down the critical path of pow.)

Paul